Which finger do I stick up when hitch hiking?

[froglady]

Hold up your pinky then people will stop because they're curious as to what the heck you're doing that for.

[glennalien]

First your thumb, if they drive past you, then you use your middle at them.

[annie apple]

Thumb when car approaches....
and middle when they pass ...

[Steve Uk]

Its the stumpy one nearest the body...Its aka a thumb